Radio frequency transceivers

ABSTRACT

A radio frequency transceiver having a printed circuit board (PCB) on which are located a plurality of components, the PCB being sandwiched between a base and a cover. The cover having a plurality of components for accommodating each of the plurality of components to separate the plurality of components into a number of virtual modules. All interconnects between the number of virtual modules are in the PCB. The PCB has a radio frequency (RF) layer, a RF ground layer, a direct current (DC) layer, and a DC ground layer. There is a plurality of via holes from the RF ground layer to the DC ground layer to provide virtual RF ground.

FIELD OF THE INVENTION

The present invention relates to radio frequency transceivers and refersparticularly, though not exclusively, to radio frequency transceiverconstructed using a virtual modular arrangement.

BACKGROUND TO THE INVENTION

Present radio frequency transceivers are constructed using severalseparate modules each having a required electrical function. Each moduleis securely mounted in a housing (a large box) and the modules areinterconnected as required using wires, cables, and so forth. Thisinvolves considerable labour, and results in a housing that isrelatively large. Many interconnects are required.

It is therefore a principal object of the present invention to provide aradio frequency transceiver where interconnects between modules aregenerally not required.

A further object of the present invention is to provide a radiofrequency transceiver where virtual modules are used.

Another object of the resent invention is to provide a radio frequencytransceiver where the construction aids heat dissipation.

A final object of the present invention is to provide a multi-layerprinted circuit board for use with such a radio frequency transceiver.

SUMMARY OF THE INVENTION

With the above and other objects in mind, the present invention providesa radio frequency transceiver having a printed circuit board on whichare located a plurality of components, the printed circuit board beingsandwiched between a base and a cover, the cover having a plurality ofmeans for accommodating each of the plurality of components to separatethe plurality of components into a number of virtual modules.

All interconnects between the number of virtual modules are preferablyin the printed circuit board.

Both the base and the cover may be made of a heat conductive material sothat at least one of the base and the cover may act as a heat sink.

Each of the means for accommodating may be a compartment in a lowersurface of the cover. Each compartment may recess into lower surface ofthe cover, and each recess may be of a depth sufficient to accommodatethe component to be located therein. One of the recesses pass maycompletely through the cover.

The compartments may be formed by pathways projecting downwardly fromthe lower surface of the cover, the pathways forming the compartmentstherebetween.

The cover may include a plurality of pathways for aligning with aplurality of DC pathways in the printed circuit board. The plurality ofpathways may extend downwardly from the cover.

The printed circuit board may include a radio frequency layer, a radiofrequency ground layer, a DC layer, and a DC ground layer. There may bea plurality via holes from the radio frequency ground layer to the DCground layer to provide virtual radio frequency ground.

The plurality of components may includes one or more of down converter,reference oscillator, at least one band pass filter, C-band synthesizer,at least one up converter, and at least one L-band synthesizer.

The DC layer may include the DC pathways to provide power connections toall the virtual modules; and each compartment may be of dimensions tosubstantially eliminate higher order modes of signal propagation.Furthermore, and more preferably, radio frequency radiation for eachvirtual module is contained within that virtual module. Each virtualmodule preferably comprises one means for accommodating and at least onecomponent.

The base may provide a radio frequency ground; and the DC layer mayinclude a pattern of a plurality of fans that, in combination with theDC ground layer and radio frequency ground layer, form capacitors tofilter radio frequency signals to ground.

In another form, the present invention provides a radio frequencytransceiver having a printed circuit board on which are mounted aplurality of components comprising the radio frequency transceiver and acover; the cover including a lower surface with means for separating thecover into at least two compartments, each compartment for receivingtherein at least one of the plurality of components to create at leasttwo virtual modules.

In a final form the present invention provides a printed circuit boardfor use with a radio frequency transceiver wherein the printed circuitboard has a radio frequency layer, a radio frequency ground layer, a DClayer, and a DC ground layer. There may be a plurality via holes fromthe radio frequency ground layer to the DC ground layer to providevirtual radio frequency ground. The base may provide a radio frequencyground; and the DC layer may include a pattern of a plurality of fansthat, in combination with the DC ground layer and radio frequency groundlayer, form capacitors to filter radio frequency signals to ground. TheDC layer may include a plurality of DC pathways to provide powerconnections to a plurality of components mountable on the printedcircuit board, the plurality of components being arranged as a number ofvirtual modules.

DESCRIPTION OF THE DRAWINGS

In order that the invention may be clearly understood and readily putinto practical effect there shall now be described by way onnon-limitative example only a preferred embodiment of the presentinvention, the description being with reference to the accompanyingillustrative drawings in which:

FIG. 1 is a perspective view of the preferred embodiment removed fromthe housing (not shown);

FIG. 2 is an underneath view of the cover of FIG. 1;

FIG. 3 is a side view of the printed circuit board of FIG. 1;

FIG. 4 is a top plan view of the cover and the printed circuit board andthe cover, the top plate of the cover having been removed;

FIG. 5 is a plan view of the printed circuit board showing theconnection between the modules; and

FIG. 6 is a top plan view of the base.

DESCRIPTION OF PREFERRED EMBODIMENT

To first consider FIG. 1, there is shown a radio frequency transceiverremoved from its housing (not shown) and having a cover 10, a printedcircuit board 12 and a base 14. The cover 10 and base 14 “sandwich” theprinted circuit between them.

Base 14 (FIG. 6), is generally planar and has a top surface that isflat. Preferably, base 14 is made of a heat-conductive material such as,for example, aluminium so that it will aid heat dissipation from thevarious components mounted on the printed circuit board. By usingaluminium the overall weight is also reduced. Effectively, the base 14acts as a heat sink and acts as a support for the printed circuit board12. It also provides a radio frequency ground. The shape of the base 14closely follows the shape of both the printed circuit board 12 and thecover 10. The base 14 may be secured to cover 10 using screws, nuts andbolts, clips, or other readily releasable yet secure fastening.

To now refer to FIG. 2, the cover 10 is also generally planar and has agenerally flat top 20. Cover 10 also has a plurality of pathways 16 andcompartments 18. The compartments 18 are sized, shaped and located toalign, preferably align exactly (within reasonable manufacturingtolerances) with components mounted on the printed circuit board 12. Thecompartments 18 may be in the form of concave recesses into the lowersurface of cover 10, with each compartment 18 being recessed to asufficient extent to accommodate the components on printed circuit board12 to be located therein. Alternatively, the compartments 18 may beformed by pathways 16 projecting downwardly to from compartments 18therebetween. Each compartment 18 may be recessed differently toaccommodate its components, or all compartments 18 may be recessed tothe same depth.

The pathways 16 are sized, shaped and located to align exactly (withinreasonable manufacturing tolerances) with the DC pathways of the printedcircuit board 12. The radio frequency signal travels along the pathways16 from one compartment 18 to another compartment 18.

In this way, the combination of the pathways 16 and compartments 18, incombination with components mounted on printed circuit board 12, createvirtual modules on printed circuit board 12, and in cover 10. As such,any radiation is kept within each virtual module and, as such, shouldnot interfere with other virtual modules. Preferably, by controlling thedimensions of each compartment 18, higher order modes of signalpropagation may be eliminated.

Like base 14, cover 10 may be made of a heat conductive material suchas, for example, aluminium. In this way it aids heat dissipation fromthe components on printed circuit board 12. This means that, in effect,the cover 10 is also acting as a heat sink.

If desired, and particularly for components on printed circuit board ofgreater height, one or more of the compartments 18 may pass through top20, as is shown in FIG 1. The shape of the cover 10 closely follows theshape of both the printed circuit board 12 and base 14. The cover 10 maybe releasably secured to the base 10 by use of one or more of screws,nuts and bolts, dips, or other readily releasable yet secure fastening.Holes 22 through cover 10 may be provided to assist this.

FIG. 3 shows the construction of the printed circuit board 12. It hasfour layers: a radio frequency layer (top) 24, a radio frequency groundlayer (second top) 26, a DC layer (second bottom) 28, and a DC groundlayer (bottom) 30.

The DC ground layer 30 is connected to the radio frequency ground 26 bya plurality of via holes, thus producing a virtual radio frequencyground. By doing this it is possible to maintain the same radiofrequency potential through the radio frequency transceiver at the radiofrequency ground 26, base 14, and cover 10.

The radio frequency layer 24 and the radio frequency ground 26 form themicro-strip transmission for the radio frequency circuits. Between theradio frequency layer 24 and the radio frequency ground 25 is adielectric layer (not shown). This may be FR-4 as using FR-4 as a basematerial may decrease manufactured cost. The thickness of the dielectriclayer determines the 50-ohm transmission line width.

The printed circuit board as shown in FIG. 4 has a number of componentsmounted thereon including, but not being limited to: down converter 32,a reference oscillator 34 two band pass filters 36, C-band synthesizer38, two low band pass filters 40, two up converters 42, and two L-bandsynthesizers 44. There maybe LNB RF in and out terminals 46, 48respectively; an output connect 50 for the power amplifies; and 70 MHzIF in and out connectors 52, 54 respectively.

Each of the components on printed circuit board is able to be located ina compartment 18 in cover 10. For example, each band pass filter 36locates in a compartment 56; C-band synthesizer 38 in compartment 58;each L-band synthesizer 44 in a compartment 60; oscillator 34 incompartment 62; and so forth. Although it is preferred for there to beonly one component for each compartment 18, there may be more than onecomponent (e.g. two or three) in a single compartment 18.

All components on the printed circuit board 12 are connected, preferablyusing 50-ohm traces. This eliminates the connection of components byinterconnects, as in the past.

The pathways 16 are sized, shaped and located to align exactly (withinreasonable manufacturing tolerances) with the DC pathways 66, as show inFIG. 5. The DC pathways 66 are in the DC layer 28. Besides functioningas the DC power connection to all the virtual modules, the DC pathways66 serve to control and monitor the virtual modules. Each virtual moduleis a combination of a component on printed circuit board 12 and itsrelevant compartment 18; and the virtual modules are separated bypathways 16.

The DC layer 28 preferably has a pattern of “fans” 64 that, incombination with the DC ground layer 30 and radio frequency ground layer26, form capacitors to filter the radio frequency signals to the ground(i.e. base 14) so that interference between virtual modules will beminimized. This, together with the virtual modules formed by thecombination of the components on printed circuit board 12 and theirrespective compartments 18, reduces the interference between the virtualmodules.

Whilst there has been described in the foregoing description a preferredembodiment of the present invention, it will be understood by thoseskilled it the technology that many variations in details of design orconstruction may be made without departing from the present invention.

The present invention extends to all features disclosed bothindividually, and in all possible permutations and combinations.

1. A radio frequency transceiver having a printed circuit board on whichare located a plurality of components, the printed circuit board beingsandwiched between a base and a cover; the cover having a plurality ofmeans for accommodating each of the plurality of components to separatethe plurality of components into a number of virtual modules.
 2. A radiofrequency transceiver as claimed in claim 1, wherein all interconnectsbetween the number of virtual modules are in the printed circuit board.3. A radio frequency transceiver as claimed in claim 1 wherein both thebase and the cover are made of a heat conductive material.
 4. A radiofrequency transceiver as claimed in claim 3, wherein at least one of thebase and the cover act as a heat sink.
 5. A radio frequency transceiveras claimed in claim 1, wherein each of the means for accommodating is acompartment in a lower surface of the cover.
 6. A radio frequencytransceiver as claimed in claim 5, wherein each compartment is a recessinto lower surface of the cover.
 7. A radio frequency transceiver asclaimed in claim 6, wherein each recess is of a depth sufficient toaccommodate the component to be located therein.
 8. A radio frequencytransceiver as claimed in claim 6, wherein at least one of the recessespasses completely through the cover.
 9. A radio frequency transceiver asclaimed in claim 5, wherein the compartments are formed by pathwaysprojecting downwardly from the lower surface of the cover; the pathwaysforming the compartments therebetween.
 10. A radio frequency transceiveras claimed in claim 5, wherein the cover includes a plurality ofpathways for aligning with a plurality of DC pathways in the printedcircuit board.
 11. A radio frequency transceiver as claimed in claim 10,wherein the plurality of pathways extend downwardly from the cover. 12.A radio frequency transceiver as claimed in claim 1, wherein the printedcircuit board includes a radio frequency layer, a radio frequency groundlayer, a DC layer, and a DC ground layer.
 13. A radio frequencytransceiver as claimed in claim 12, wherein there is a plurality of viaholes from the radio frequency ground layer to the DC ground layer toprovide a virtual radio frequency ground.
 14. A radio frequencytransceiver as claimed in claim 1, wherein the plurality of componentsincludes one or more selected from the group consisting of: downconverter, reference oscillator, at least one band pass filter, C-bandsynthesizer, at least one up converter, and at least one L-bandsynthesizer.
 15. A radio frequency transceiver as claimed in claim 12,wherein the DC layer includes the DC pathways to provide powerconnections to all the virtual modules.
 16. A radio frequencytransceiver as claimed in claim 5, wherein each compartment is ofdimensions to substantially eliminate higher order modes of signalpropagation.
 17. A radio frequency transceiver as claimed in claim 1,wherein radio frequency radiation for each virtual module is containedwithin that virtual module.
 18. A radio frequency transceiver as claimedin claim 1, wherein each virtual module comprises one means foraccommodating and at least one component.
 19. A radio frequencytransceiver as claimed in claim 1, wherein the base provides a radiofrequency ground.
 20. A radio frequency transceiver as claimed in claim12, wherein the DC layer includes a pattern of a plurality of fans that,in combination with the DC ground layer and radio frequency groundlayer, form capacitors to filter radio frequency signals to ground. 21.A radio frequency transceiver having a printed circuit board on whichare mounted a plurality of components comprising the radio frequencytransceiver, and a cover; the cover including a lower surface with meansfor separating the cover into at least two compartments, eachcompartment for receiving therein at least one of the plurality ofcomponents to create at least two virtual modules.
 22. A printed circuitboard for use with a radio frequency transceiver wherein the printedcircuit board has a radio frequency layer, a radio frequency groundlayer, a DC layer, and a DC ground layer; the DC layer including aplurality of DC pathways to provide power connections to a plurality ofcomponents mountable on the printed circuit board, the plurality ofcomponents being arranged as a number of virtual modules.
 23. A printedcircuit board as claimed in claim 22, wherein there is a plurality ofvia holes from the radio frequency ground layer to the DC ground layerto provide virtual radio frequency ground.
 24. A printed circuit boardas claimed in claim 22, wherein the base provides a radio frequencyground.
 25. A printed circuit board as claimed in claim 22, wherein theDC layer includes a pattern of a plurality of fans that, in combinationwith the DC ground layer and radio frequency ground layer, formcapacitors to filter radio frequency signals to ground.